Stabilized gasoline



Bagl- 19, 1943'. H. RosENvl/ALD ET AL 2,308,783

STABILIZED GASOLINE Original Filed April 30, 1938 OLKYL .SU STITUTED DJLKYL SUBSTTUTED 5 /MXFD Z/(YL SUBSTITUTED Patented Jan.' 19, 1943 2,308,783 STABILIZED GASOLINE Robert H. Rosenwald an Chicago, Ill., assignors ucts Company, Chicago, lll.,

' Delaware Original application d Joseph A. Chenicek,

to Universal Oil Proda corporation of v April 30, 1938, Serial No. 205,356, now Patent No. 2,250,

501, dated July 29, 1941. Divided and this application April 8, 1941, Serial No. 387.467 r 4 Claims.

This application is a division of our co-pending application Serial No. 205,356 which was filed April 30, 1938, now Patent No. 2,250,501 of July 29, 1941.

This invention relatesmore particularly .to a process of treatment applicable to lower boiling fractions of cracked distillates within the gasoline range although it is also applicable to heavier distillates produced by the fractionationof cracked products and to corresponding fractions from the primary distillation of crude petroleums or other hydrocarbonaceous materials such as coaland shale.

The process is concerned specifically with the use of cert-ain definite types of inhibitors .to materially arrest the deterioration to which hydrocarbon distillates containing appreciable quantities of oleiinic and other unsaturated hydrocarbons are subject. The art of using inhibitors in unstable gasolines is n-ow one of comparatively long standing and a large number of individual compounds. and classes of compounds have been developed for practical use, all of which apparently possess the characteristic of being more or less readily oxidizable so that the peroxidic compounds which are primarily formed when olefincontaining gasolines are in contact with air or other oxidizing gas mixtures are decomposed and the sequence of the chain reactions leading to the formation of ,higher boiling polymers and resinous products which cause the deterioration of the gasoline in respect to color, gum content, a-nd antiknock value is stopped for a time depending upon the efdciency of the inhibitor, the degree of unsaturation of the oil and the extent of its exposure.

amines, and aminophenols and crude primary products containing these compounds, and no basic claim is made herein tothe broad use of any of these class. The present invention is specially concerned with a limited group of compounds which have been found to possess exceptionally goodl inhibiting potency combined with resistance to accidental removal by contact with water or caustic soda' which occurs at many points in the storage systems of oil reneries.

In one specific embodiment the present invention comprises the treatment of unstable gasolines, particularly cracked gasolines, to materially arrest 'the deterioration thereof by adding to said gasolines relatively small percentages of N- methyl-N-octyl aminophenols. The octyl group may be of a normal or branched character and thesubstituted amino group may be in the ortho, meta, or para position with respect to the hydroxyl group although in general the compounds of greater potency fall within the general class of those of the para substituted variety.

We have'shown as -a result of considerable number of experiments in which ldieren-tly substituted alkyl Aaminophenols were tested lthat greater advantages are gained by utilizing as inhibitors alkyl amino-phenols in which there is substitution of both amino hydrogens by difierent -alkyl groups over utilizing those characterized by substitution with identical groups or by substitution of one amino hydrogen with one group even though the total number of carbon atoms in the substituting groups is the same in all cases. The advantages gained include greater inhibiting potency, greater solubility in gasolines and improved resi-stance to extraction with water or alkaline solutions Ito which gasolines may be exposed during storage conditions, on account of the decreased solubility of the mixed substituted compounds. These advantages were unexpected and unpredictable from any study of chemical composition or constitution relating to inhibitors and form the' principal subject matter of the present invention. The actual degree of these effects will be indicated in a succeeding illustrative and numerical section.

Compounds of the present character are made from aminophenols by successively replacing the amino hydrogens with the desired alkyl groups. These step-wise substitutions are made generally by the interaction of molal proportions of an amino-phenol with an valkyl chloride or an alkyl sulfate using an alkaline condensing agent according to the following equations which show the manufacture of N-methyl-n-iso-amyl paminophenol:

` H-N-H p-amino phenol isoamyl chloride N-isoamyl-p-amino phenol H--N-i-Culn Methyl chloride amount of alkyl halide. A catalyst is not neces- The followingspeciiic example is given of the manufacture of a compound falling within the gasolines, with various types of antiknock compounds such as tetra ethyl lead and with special types vof inhibitors which are directed to the preservation of color or other specific properties.

the slightly yellow tingev characteristic of cracked scope of the invention, the method shown being 5 The following tabulation lnCllldeS One Set 0f definitely applicable to .the manufacture of other data obtained in connection with the type of similar compounds by varying the alkyl groups compounds which characterize the present invenin rthe reactants according to their relative tion. This set of data includes the eiect on the molecular Weights. copper dish gums and the oxygen bomb stability To prepare N-n-octyl-N-methyl-p-aminophelo of a gasoline toV which 0.01% of the inhibitors no1, the mixture tabulated below was Areiluxed were added.

Copper dishgum, Oxygen bomb stability, Percent removed r Eective mg./100 cc. ,induction period, min. v

mhibiior I @a lisis este ont las ear les: este original gasoline a7 21s 10c 85 85 75l 4 1 25 325 29o 105 15 s1 7 15 s 32o 285 105 15 sv 1 7 1o 335 aso 31o o e 12 9 13 39o 425 405 o o for 12 hours under atmospheric pressure. The eiective inhibitor ratio given in column 1 of the tabulation indicates the relative value of Methy1 p aminopheno1 Sulfa j lgl 25 the compounds as inhibitors. The values were Sodium bcarbonate 52 substantially the same when calculated on a molal n octyl brnmidp 45 basis although a slight decrease was observable Ethyl alcohol 200 as the molecular weight increased. It will be i e seen from the table that theA higher molecular After the period of digestion the total reactants weight Cohlpounds were Substantially unaffected Were poured into Water. and the aqueous and Oil by Water or caustic Washing since there was no layers were extracted with a. small volume of material change in the copper dish gum 0r the ether. Ether extracts were then heated to volaoxygen bomb stability of the gasolines to which tilize the ether and then distilled under an abthey were added solute pressure of 4 mm. of mercury. 'I'he pri' The attached curves designated as Figure 1 mary dlstlllation gave the results Shown belOW- are introduced to exemplify the more general Fraction l Q 2.5 parts by weight aspects of the invention. These curves were made Boiling range 1Z0-167 C. up to indicate the data obtained in a large num- Fraction 111 329 parts by Weight ber of experiments. Referring to the figure, it -Railing range 163 170 C. 40 will be seen that curve I shows the variation of Residue 5 0 parts by Weight the eiective inhibitor ratio with the total carbon atoms in substituting groups of mono-alkyl sub- 1N3n-octy1- N-methyl p-aminopheno1- stituted aminophenols. Curve 2 shows the same Red1st1llat1on of fraction II which corresponded relationship when dialkyl substituted compounds to a 70% yield of the desired compound showed are considered in whichthe substituting groups a COIlStant bOlllrlg P01111? 0f 163 C- 45 are the same. Curve 3 which it will be observed The amounts of the present classes of come is higher than the other two at all points below pounds Which are necessary llo properly inhibit 18 carbon atoms shows graphically the data the deterioration of unstable gasolines will obobtained with mixed alkyl substituted amino.. v iously dependupon the instability of the par- 5o phenols. From this data it is obvious Ythat the ticular gasoline at hand and the potency of the most effective inhibitors are those di-substituted indivldual compound selected. As a rule it is aminophenols in which the substituting groups seldom necessary to employ more than 0.1% of are different. any of the inhibiting compounds and usually Del- We claim as our invention: centages of the order of 0.01% are sullcient. 1. A process for the treatment of gasolines Since the present compounds are considerably subject to deterioration of their desirable propermore Soluble 1n gasoline than those in which ties on storage, which comprises adding thereto the alkyl groups are the same, the addition of amounts of N-methyl-N-octyl aminophenols 'the necessary Small' amOllntS to gasoline eonequal to less than 0.1% by weight of said gasotamed in large storage tanks is more simple and line. l l more easily eiected than when inhibitors of 2. Apr'ocess for the treatment of gasolines sublesser solubility are employed in which cases ject to deterioration of their desirable properties it is frequently necessary to employ a long period on storage, which comprises adding thereto of mechanical mixing or an auxiliary solvent to amountsA of N-methyl-N-octyl-p-aminophenols assist in the dispersion of the inhibiting com,- equal to less than 0.1% by weight of said gasoline. pounds. In the present instance a minimum of 55 3. A process for the treatment of cracked gasomixing is required and solvents are not necessary. f lines subject to deterioration of their desirable 1n addition, owing to the relatively low water and properties on storage, which comprises adding alkali solubility of the preferred compounds, thereto amounts of N-methyl-N-octyl-p-aminothey may be used in gasollnes which are not dry phenols equal to lessthan 0.1% by weight-of said or which are stored over water or alkali to pregasoline. vent corrosion of the tank bottoms. These n- 4. Motor fuel comprising unstable gasolines` hibitors may be also employed in conjunction containing la relatively small amount of N- with other compounds of specific character .such methyl-Noctyl-p-aminophenols. l as the dyes which are frequently used to mask ROBERT H. ROSENWALD.

JOSEPH A. CHENICEK. 

